Thank you to all who attended George’s presentation, Case Studies in Antithrombotic Therapy, made on Friday, October 12 at the Quest Diagnostics Case-oriented Symposium on Bleeding and Thrombosis in Crystal City, VA, near Washington, DC. As promised, here is my presentation in 6-per-page handout format. Please click the link and feel free to download the file.
After the talk, Merve Sahud, MD, director of the west coast Quest Diagnostics Nichols Institute coagulation service, provided the following helpful remarks:
- Before using thrombolytic therapy such as Activase, perform a fundoscopic exam to check for diabetic hemorrhagic retinopathy, or other hemorrhagic ophthalmic conditions to avoid an intraocular bleed.
- There may be a tendency to overdose with fibrinolytic inhibitors such as tranexamic acid and with synthetic factor VIIa preparations in severe bleeding secondary to anticoagulant therapy, particularly in people over 70. Such an overdose may lead to stroke. This issue arises especially when the new oral anticoagulants such as dabigatran or rivaroxaban are used, as the means for reversal that work for heparin or Coumadin do not work for these drugs. Dr. Sahud suggests that renal dialysis, although time-consuming, is the best current approach to resolve hemorrhage.
- The dyspepsia reported by patients in the dabigatran trials could conceivably relate to the use of lactose as a filler in pill preparation. It may be that lactase-deficient individuals are the ones who report stomach pain.
- Contrary to my suggestions regarding the use of standard coagulation testing methods to monitor rivaroxaban, Dr. Sahud points to Samama MM, Contant G, Spiro TE,et al. Evaluation of the prothrombin time for measuring rivaroxaban plasma concentrations using calibrators and controls: results of a multicenter field trial. Clin Appl Thromb Hemost. 2012:150-8, which suggest the prothrombin time may be used to monitor rivaroxaban.
- And relative to my case presentation of an individual with an INR of 11, this implies a near-absence of factors II, VII, and X, and is certain to be associated with bleeding.